Saw-tooth.



PATENTED MAY 16, 1-905.

J. H. Mel-BAN.

I SAW TOOTH. Arrmourox FILED KOV.3,1904.

INVENTOR 22 ff. W01; eaiz,

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ATTORNEY Patented May 16, 1905.

PATENT OFFICE.

JOHN H. MoLEAN, OF VANCOUVER, CANADA.

SAW-TOOTH.

SPECIFICATION forming part of Letters Patent No. 790,072, dated May 16,1905.

Application filed. November 3, 1904. Serial No. 231,215.

To all whom it may concern.-

Be it known that I, J oHNH. MoLnAN, a citizen of the Dominion of Canada,residing at Vancouver, in the Province of British Columbia, Canada, haveinvented new and useful Improvements in Saw-Teeth, of which thefollowing is a specification.

My invention relates to an improved sawtooth designed especially as whatis locally known in the trade as a mitering-saw, but is equallyapplicable to the general purposes of ripping and cross-cutting, as theform of its teeth is well fitted to perform either work.

In designing saw-teeth the error is commonly made of endeavoring'to cutthe grain of the wood on each side of the saw thickness by providing theteeth with acute chisel edges,

a the tooth to remove the wood between the two side cuts. The teeththerefore merely roll andtear this material out instead of cutting itclear away and throwing it'into the gullet. This rolling action causesconsiderable waste of power and rapidly heats the saw. This constructionof tooth is also open to the objection that the acute edge is quicklydulled, and. the points of the teeth being insufficiently backed up withmetal are subject to serious damage if they encounter a hard obstacleduring the cut.

The tooth which I have invented and which is the subject of thisapplication is carefully designed to avoid these faults, as the tops ofthe teeth out across the entire gage thickness of the saw and thematerial is removed at once into the gullet. As a result, a saw theteeth of which are shaped and ground in accordance with my instructionsis susceptible of a high rate of feed, will last much longer without thecutting edges of the teeth becoming dull, and the points of the teethare well backed up with metal, so they arenot liable to such extensiveinjury when they meet with an obstacle in their out. As evidence thatthe work of removal of the saw-cut is better performed, the saw,although made with very little. or no cutting-face side of each tooth.

set, does not heat, and the cut is clean and smooth. The particularmanner in which these teeth are formed is fully described in thefollowing specification and illustrated in the drawings which accompanyit.

Figure 1 is a perspective view of a portion of the saw, showing a seriesof teeth. Fig. 2 is a side elevation thereof. Fig. 3 is a plan viewthereof. Figs. 4 and 5 are sections taken, respectively, on the lines t4 and 5 5 of Fig. 2. Fig. 6 represents a piece of Wood having a saw-cutacross it for mitering purposes.

In the drawings theteeth are represented by 2, and the gullets 3 betweenthem are cut so as to, afford a slight hook to the cuttingbeing aboutequal to the gage thickness of the saw, and the plane of grinding ofthis top is also sloped slightly downward to the This lateral downwardslope toward the cutting-face side of each tooth is designed to make theextreme top of the cutting edge square in end elevation to the face ofthe blade, (see Fig. 3,) as without it the intersection of the twoinclinesthat of the cutting-face and the backward slope or rake of thetop of the.tooth would be inclined downward from the cutting-face sideof each tooth. The incline of this intersection is corrected in themanner described, and the cutting edge of the points of the teeth arebrought square across the thickness of the saw, because for generalpurposes it is desirable that the bottom of the saw-cut shall be squareto the sides. Teeth so formed and ground will be found to be muchcheaper to cut in the first instance and simpler to maintain, besidesgiving a much greater efiiciency in the work performed, and

will leave a cleaner and smoothercut surface.

The hook of the gap 3 enables a sufficiently acute angle to be obtainedat the point of the tooth, with a moderate backward slope of the top 5,which moderate slope, combined with the moderate angle of the bevel ofthe cutting-face, enables a cutting edge to be obtained at the point ofthe tooth across the whole width of the saw-cut, so that each" tooth notonly cuts its way, but at once removes the material of its cut into thegullet, and no necessity is experienced for introducing a drag-tooth toperform this duty, as is common with saws designed for such work, andthe slight slope toward the cutting-face side of each tooth brings thecutting edge of the tip of the tooth square to the face of thesaw-blade.

Having now particularly described my invention and the manner of itsoperation, I hereby declare that what I claim as new, and desire to beprotected in by Letters Patent, 1s

1. A saw comprising uniformly-constructed teeth the sides of each toothbeing parallel to one another in profile and the front cutting-faces ofthe teeth moderately hooked or undercut and ground to moderately-acutealternately-reversed angles to the face of the saw-blade, the bottoms ofthe gullets semicircular and horizontally straight across the bladethickness, the tops of the teeth sloped 3 downward moderately from thefront face and the plane of grinding sloping alternately in adjacentteeth downward toward the cuttingedge side of each.

2. A saw, comprising uniformly-constructed teeth, the side faces of eachbeing Hat and the side faces of each tooth being parallel with. eachother, the thickness faces of each tooth being ground tomoderately-acute and opposite angles reversed on adjacent teeth to formU-shaped passages between adjacent teeth, and extending at an angle tothe faces of the saw, the adjacent thickness faces of adjacent teethbeing parallel to each other, the bottom of the passages beingsemicircular and extending horizontally across the saw, the passagesbetween adjacent alternating pairs of teeth being disposed atoppositeequal angles to the plane of the saw-body, the tops of the teeth slopeddownwardly moderately from the front face and the plane of grindingsloping alternately in adjacent teeth downward toward the cutting edgeside of each, substantially as shown and described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

JOHN H. MCLEAN.

Witnesses:

ROWLAND BRITTAIN, M. BRITTAIN.

